[chappy84]

I recently Upgraded from 3:73's with 33" tires to 4:88's for 33's and 35" tires. I have a four speed auto and am wondering what the best way to break in the gears and lockers is......................Change fluids after 500 miles?
My wife had this done for me while I was in Alaska so I wasn't able to drill the mech.

Thanks in advance for your replys.

[neatocj]

Use them.

I would change the oil at 500 and check for any wearing or doom shavings.

[BoHeck]

drive softly for a while, no hard accelerating, no towing. then change the fluid at 500 to get the metal shavings out of it, and you should be good to go.

[GOLENJEEPTJ]

No hard braking or accelerating for first couple hundred!

[Jerry Bransford]

This from Randy's Ring & Pinion...

"What is the break-in proceedure for a new set of gears?
All new gear sets require a break-in period to prevent damage from overheating. After driving the first 15 or 20 miles it is best to let the differential cool before proceeding. I recommend at least 500 miles before towing. I also recommend towing for very short distances (less than 15 miles) and letting the differential cool before continuing during the first 45 towing miles. This may seem unnecessary but I have seen many differentials damaged from being loaded before the gear set was broken in.
I also recommend changing the gear oil after the first 500 miles. This will remove any metal particles or phosphorus coating that has come from the new gear set. "

[chappy84]

Thanks guys! I will take it easy.......................man that's hard when you are so excited.

[Nonya]

I hate to say this BUT look at all the new cars people buy...ever hear of anyone breaking in their rear?Drive it like normal and if something goes wrong it wasn't right inb the 1st place.I've done 100's of rears....never did anything but drive them normal and i never had one fail.

[cmc1]

I took the randys gear method and drove around about 15 miles very slowly.I did the setup myself and had everything nominal.the tech i talked to at randys told me to do this and then touch my dif.cover.Its almost to hot to touch. After 500 miles it was just very warm with the same miles and driving style.I can see how you could destroy parts with them that hot.

[Cowboy1629]

Originally Posted by cmc1

I took the randys gear method and drove around about 15 miles very slowly.I did the setup myself and had everything nominal.the tech i talked to at randys told me to do this and then touch my dif.cover.Its almost to hot to touch. After 500 miles it was just very warm with the same miles and driving style.I can see how you could destroy parts with them that hot.

When I regeared my front and rear I did the same thing. When I touched the differentials they were almost too hot to keep your hand on. Yesterday I just completed the install of NorthRidge's built Dana 44 with an ARB locker. After driving it roughly 15 miles the differential was only slightly warm. Might be the difference between a D44 and a D35, not sure but I know it wasn't near as warm as the D30 and D35 that I did. Mine were within spec too and showed no ware after two years of service.

I have also driven a new vehicle without worrying about breaking in the gears but what the heck, it was under warranty.

[chappy84]

I was told that I also need to put 500 miles in four wheel drive to break in the front gears. Any truth to this????